<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        let x = 100
        x--
        console.log({ x: x })
        x += ""
        console.log({ x: x })
        let y = "100"
        console.log({ y: +y })
        console.log({ y: 100 / +Infinity })

        let isboy
        console.log(isboy ? "男" : "女")
    </script>
</body>

</html>